All safety equipment used in various working environments should comply with specific standards. This scientific paper is about research and analyses of the compulsory standards for eyeprotection in working environment. It includes methods for mechanical tests according to the standard further explained and virtual testing by using a numerical model. A physical reference model was used that complies with the aforementioned standard. The main purpose of this scientific paper is showing the behaviour of safety glasses during their mechanical test but in virtual environment. The standard EN166:2001- “Personal eye protection equipment” describes the test and the requirements that should be fulfilled for granting confirmation. The aim of this paper is the conduction of the mechanical test described in the standard EN166 by using virtual simulation, analyzing the results and suggesting possible modifications on the safety equipment.

The damage that occurs on the teeth flank of cylindrical gears is a complex phenomenon and depends on many factors. The most common cause for these damages is the high contact stress of the meshing gears. Although this contact pressure, by itself, cannot be a criterion for determining the durability of the gears, a good correlation has been found between the contact or Hertz pressure and the damage that occurs on the tooth flank. This paper analyzes the influence of the pressure angle α on the contact stress. Analytical calculation according to the ISO 6336-2:2006 and finite element method (FEM) was used for the analysis. Four cases were analyzed with a change in the pressure angle, i.e., cylindrical spur gears and pressure angles of 17.5°, 20°, 22.5° and 25°. In the results, it was noted that by increasing the pressure angle, the contact stress decreases. It can also be concluded that by increasing the pressure angle, the difference in the results between the analytical and FEM analysis, also increases.

Shock absorbers are main elements into construction of train wagons that secure protection from longitudinal forces which appear during transitional regimes of movement. Besides, development of new constructive solutions for shock absorbers is quite popular development of their working mathematical models. This paper presents modern shock absorber with elastic block made from polymer elements that increase quantity of absorbed energy. This is achieved by increasing the stiffness characteristic of polymer elastic block. The construction is relatively simple and technology used to create the construction is with more or less low price. If there is not enough elastic stiffness of the polymer block, there is a possibility for not meeting the UIC (International Union of Railways) norms for absorbed energy. Therefore, according to the mentioned characteristic, shock absorbers are divided into three groups. The mathematical model presented in this paper allows calculating the necessary elastic characteristic of the polymer block for a short time. Differential equation of movement of the shock absorber elements is presented in this paper. Force change of polymer block for various impact velocities participates in the differential equation of movement where initial velocity V 0 and the current meaning of the velocity x  are taken into consideration. The presented equation is solved by using program language MATLAB/Simulink by developing a simulation model.